Location: Old Gibson Scrapyard, North of Novac
Getting your hands on the Big Boomer is kind of a tricky proposition. It’s currently being held by a nice old lady who is related to a few quests. As such it’s somewhat ill-advised to kill her as soon as you meet her although it might be doable before leaving Novac. Regardless this nice old lady is the one holding on to the gun and there’s actually no way to get it without some form of conflict.
The problem here is that the old lady has the weapon equipped. Even if you give her something to make her unequip it, or pickpocket the ammo for it so that she chooses to do so, she will always notice when you attempt to take the gun. That doesn’t mean we have no options:
1.First and foremost you can just murder the old lady. Loot her body for the gun and a key that she’s carrying. This key is used during a quest at the REPCONN facility nearby. Try not to do this dark deed until she’s helped you start up Ed-E’s data logs though.
2.This one is a bit trickier as you’re going to pick a fight. Take out a silenced weapon, or melee weapon, and use it to kill her dogs that are outside. Now do the same inside. If done properly you should be able to kill them all without alerting her. With that done take out a weak weapon, like a 9mm pistol, and get ready. Walk up to the old lady, put the gun away, punch her and then take it back out. She should draw her Big Boomer. Shoot her arm to cause her to drop the gun allowing you to quickly grab it and flee. When you return to her some hours later she should have gone peaceful again but this isn’t 100% so save your game before you attempt this.